Keyboard and message system

ABSTRACT

A keyboard entry digital data transmission and reception system employing a one-handed keyboard is disclosed. The novel keyboard arrangement and the logic circuitry associated therewith permits single data characters to be rapidly entered by a plurality of sequential key depressions which uniquely define each character.

United States Patent [191 Hilborn et al.

1 1 Sept. 3, 1974 [54] KEYBOARD AND MESSAGE SYSTEM 3,491,355 1/1970Harrold 178/79 3,493,922 2/1970 Laas..... 340/365 [75] lnvemm- Frammgham3,772,597 11/1973 Stover 178/17 c Joseph D. Brabel, Concord; Kenneth J.Bray, Medway, all of Mass.

[73] Assignee: The United States of America as Prim ry ExaminerThOmaS A.Robinson represented by the Sec t f th Attorney, Agent, or FirmHerbertE. Farmer; Nathan Department of Transportation, Edelberg; Harold P.Deeley, Jr. Washington, DC.

[22] Filed: Jan. 30, 1973 [21] Appl. No.: 327,953 [57] ABSTRACT [52] U5.Cl. 178/79, 178/17 C, 340/365 R A k yboar entry igi l data transmissionand recep- [51] Int. Cl G08b 1/00, H04b 1/00, H041 15/02 i n y memploying a one-handed keyboard is dis- [58] Field of Search 178/ 17 C,79, 80, 81, 175; closed. The novel keyboard arrangement and the logic340/365, 172,5; 235/ 145 R circuitry associated therewith permits singledata characters to be rapidly entered by a plurality of sequential [56]References Cited key depressions which uniquely define each character.

UNITED STATES PATENTS 3,361,875 1/1968 Banfalvi et a1 178/79 21 Claims,4 Drawing Figures .8 2o 26 zsezoit aeH Lm I2 DATA ]NE /I4 KEYBOARD LINESROM 8 UNES STORAGE SPC gl/SS LATCH DATA CK IN CK our 22 m SEEE$ZE| s9 24g n NUlx BER N x7 IE /-\Y REGISTER UP/DOWN CK DOWN 3s STEERING 4o rg CKUP COUNTER T LOGIC ,cLEAR KEYBOARD 54 i 42 5 i c g 7o C zERo r /CLEARALL c DETE+CTOR 44 i e MESSAGE PRESENT REGISTER /TRANSMIT PATENTED SE?914 INPUT SHEET 1 0F 3 A T ABC DEF e H 1 2 3 4 IJK L MNO PQRS 5 6 7 8shiFT TUV 'WXYZ space FIG. 1

so 82 I6 RECEIVER SQR T'AL F0 VOICE TO 8 L s STORAGE 8 LINES SYNTHESIZERPARALLEL DATA DATA CONVERTER CK CK OUT ROY GO CHAR RDY Q uR/DOWN vvORDCOUNTER 92 94 l 4 ZERO DELAY DETECTOR 8 9O l MESSAGE PRESENT DELAY EEifi E REGISTER FIG. 3

KEYBOARD AND MESSAGE SYSTEM ORIGIN OF THE INVENTION The inventiondescribed herein was made by employees of the United States Governmentand may be man ufactured and used by or for the Government forgovernmental purposes without the payment of any royalties thereon ortherefor.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to the coding and subsequent digital transmission andreception of data and to the presentation of the thus transmitted andreceived data in readily usable form. More specifically, this inventionrelates to a keyboard entry data transmission and reception systememploying a one-handed keyboard wherein single characters or informationbits are uniquely defined by a plurality of sequential key depressions.Accordingly, the general objects of the present invention are to providenovel and improved methods and apparatus of such character.

2. Description of the Prior Art The necessity of increasing the speedand accuracy of data transmission is particularly evident in the fieldof air traffic control. At the present time most information exchangebetween an aircraft and ground controllers is accomplished by voicetransmission. The present overload on voice transmission links asutilized for air traffic control is forcing the need for digital messagetransmission so as to free air time and permit an increase in the numberof messages which can be transmitted per unit of time.

In order for digital data link transmission techniques to be acceptableor adaptable for widespread usage, some form of keyboard entry ofinformation is required. The most basic form of keyboard data entrydevice, of course, comprises the existing standard typewriter keyboard.The standard keyboard typewriter, however, originated as a purelymechanical device. Because of the initial crudity of the mechanicallinkages available, the characters on the keys of early typewriters wereintentionally positioned in a somewhat awkward arrangement so as to slowthe typist to a speed compatible with capabilities of the mechanicalapparatus. The original typewriter keyboard layout has persisted to thepresent time, although substantial equipment improvements have beenmade, for the very basic reason that a change to a different characterlayout would require the retraining of millions of typists as well asthe rebuilding of all existing typewriters.

Returning to a consideration of the air traffic control problem, withwhich the present invention is concerned but not limited, spaceconstraints within aircraft cockpits are severe and this factor alonedictates that the means for generating information for the input to adigital message transmission system must be in some form other than astandard typewriter keyboard. As a further factor dictating against theuse of a standard typewriter keyboard, obviously an aircraft crewmancannot be expected to have two hands free for efficient operation of anormal QWERTY keyboard.

Special purpose key sets have been developed and are presently in use.The well known Stenotype machine represents one example of one suchspecial purpose keyboard. Extremely high input rates are possible with aStenotype machine through the use of chord keying. However, use of aStenotype machine requires an extended period of training and the outputis in coded form rather than in normal English text.

To briefly summarize the foregoing, operations within complexman-machine systems are imposing increasing needs for keyboard entry ofinformation under conditions where two-handed keying is not feasible inthe face of requirements for the performance of other concurrent tasks.The piloting of airliners, operation of police vehicles equipped withdigital communication links and the checkout of complex military andspace systems represent examples of technological areas wherein, even inthe absence of space constraints, use of a standard typewriter keyboardwould be inefficient when keyed by only one hand. Accordingly, a needclearly exists for a simple one-handed keyboard and associated logicsystems which may be used for communication purposes. Such equipment,while having initial utility in an area such as air traffic control toreplace the present inefficient use of voice transmission, may beapplied to a general purpose one-handed typewriter. A typewriter capableof being produced in a pocketsize version would have wide application tostudents taking lecture notes, or for other persons who must regularlymake records, and a similar input device coupled to a speech synthesizerwould permit deaf mutes to communicate with the public at large.

SUMMARY OF THEINVENTION The present invention overcomes the abovebriefly discussed and other deficiencies and disadvantages of the priorart by providing a limited-key input device having the capability ofeasy insertion of alphanumeric information. In accordance with thepresent invention a keyboard data entry device, with keys havingelectrical contacts which actuate digital logic circuitry, is employed.In the use of a preferred embodiment of the invention, the depression ofone key provides an electrical signal which is later modified or addedonto by a signal resulting from the depression of a second key;character or bit presentation resulting only after the depression of thesecond key. The present invention thus comprises a uniquely organizedone-handed keyboard, with a limited number of data entry input keys, andassociated logic circuitry whereby single characters are uniquelydefined by sequential key depressions.

In the disclosed embodiment of the invention, which is directed to anair traffic control application, the keyboard is used to enter a messagewhich is presented on a printer or a volatile display in real time forproofreading; the message comprising a number of two stroke definedcharacters. The displayed message is simultaneously stored in binaryform so that, when proofreading is completed, the message, may betransmitted at high speed to a remote terminal where it may, forexample, be used to activate a speech synthesizer which then pronouncesthe message at a normal speaking rate. The digital logic circuitryassociated with the onehand keyboard permits the generation andtransmission of normal English text or of mnemonically coded messages.When mnemonically coded messages are transmitted, the logic circuitryrecognizes that such a message would normally be followed by digits, forexample indicative of altitude or heading, and thus the circuitryperforms an automatic shift to numerals until such time as the space keyis depressed whereupon the system resumes use of double enteredalphabetic characters.

BRIEF DESCRIPTION OF THE DRAWING The present invention may be betterunderstood and its numerous objects and advantages will become apparentto those skilled in the art by reference to the accompanying drawingwherein like reference numerals refer to like elements in the severalfigures and in which:

FIG. 1 depicts a representative keyboard layout in accordance with theinvention;

FIGS. 2A and 28, when placed side by side, are an electrical circuitblock diagram of data entry, storage and transmission circuitry inaccordance with an embodiment of the invention employed in air trafficcontrol; and

FIG. 3 is an electrical circuit block diagram of a receiver which wouldbe employed with the transmission circuitry of FIGS. 2A and 28.

DESCRIPTION OF THE PREFERRED EMBODIMENT Solely for purposes ofexplanation, the present invention will be described in the environmentof a data link between an aircraft and a ground controller. As notedabove, the invention has much broader utility. With reference to FIG. 1,a basic keyboard layout in accordance with the present invention isdepicted. In considering the design of such a limited key set; i.e., akey set having fewer keys than the number of characters which may beprinted or words which may be pronounced; it is desirable to placecharacters on the keys in an easily remembered sequence. Such characterplacement permits use of a coding scheme which is already familiar to anappreciable proportion of the population of potential users of theapparatus. An additional design consideration is to arrange the keylayout in the interest of permitting the full use potential of one hand.In the keyboard of FIG. 1, these design considerations have beenfulfilled by arranging the letters and numerals in alphabetical andnumerical order, by allocating letters to keys such that the keying ofthe first two letters of the words in the [CA phonetic alphabet willuniquely define each letter of the English alphabet and by using akeyboard layout which permits four finger operation.

With the keyboard layout of FIG. 1, since the keys are convenientlyplaced under the fingers of one hand, rapid keying is possible eventhough two key strokes are required for each letter. to be typed. In thebasic form depicted, the keyboard uses only 26 of the possible 100combinations of two key strokes and there are accordingly 74 additionalcombinations which may be employed. By way of example, in the Englishlanguage there are approximately 45 two and three-letter combinationswhich occur with high frequency and some or all of these combinationscan be specified with two-key combinations not used for the phoneticalphabet. Thus, after an operator has learned basic keying of the [CA0combinations, he may be taught the second-order combinations in order toreduce the number of key strokes required to generate a given number ofletters. A third level of complexity may, obviously, also be introducedin the interest of utilizing-other common combinations of Englishcharacters in order to further reduce the number of key strokes requiredto produce a given amount of text.

The immediately preceding brief discussion is aimed at the generation ofnormal English text. For special purposes, such as air traffic control,it becomes possible to use other combinations to produce mnemonic codingof special purpose messages. In the preferred embodiment, thecombinations required to produce the phonetic alphabet are retained, butthe remaining ca pacity of the keyboard may be filled in a variety ofways. Thus, again considering the example of air traffic control,two-letter mnemonically coded messages may be generated such as:

Char- Ground to Air Air to Ground acter Transmission Transmission 02WEather (provides autorequest for WEather matic transmission ofinformation weather information) 05 squaWK identification not used maybe followed by a numeric code) 07 You May (permissnot used ion granted)10 Contact Wide area not used control (ARTCC) ll Contact Approach notused control 12 Contact Departure not used control 13 Contact Ground notused control [5 AcKnowledge (ment) AcKnowledge (ment) 19 Contact Towernot used or this may be a request for the frequency if it is notautomatically supplied by ground 25 Dump Information Dump Information(means for clearingthe display, not a transmitted message, or transferto another controller) 26 Flight Level? not used in two-character(request for altitude format information) 28 not used Emergency Requestfor priority in use of voice channel 34 not used may l Go Higher?(request for a higher altitude) 36 not used may I Go Lower? (request fora lower altitude) 46 Hold Level (maintain Holding present Level presentaltitude) (might be followed by digits to indicate reaching a requestedaltitude) 49 Hold after Taxiing Holding after Taxiing 51 not usedInitial Contact with a new controller. (should automatically provideflight no., aircraft type and other pertinent info.)

52 If Feasible If Feasible 56 I Locate you I Locate the traffic (radarcontact) you have pointed out 62 LEave a holdor LEaving (rolling, takingrestriction off, departing, etc.)

67 Lost Message Lost Message (request (request for refor retransmission)transmission) 68 what is your Lowest not used in two-character Speedpossible? format 7l you are Now Cleared not used 76 Not Located (can'ttraffic Not Located find you on radar) 79 not used in tworeport ofreaching the character format OUter marker 80 Stay With me (remain notused on this frequency) 83 Restriction Gone not used (listed) Thank YouThank You 92 not used in twoestimated Traffic Delay -Continued Char-Ground to Air Air to Ground acter Transmission Transmission characterformat requested 99 TUrbulence (possible TUrbulence report from wake ofprevious aircraft) With respect to the use of AK for acknowledgement, asset forth in the above tabulation, it is to be noted that present voicetransmission techniques require that any commands or advisories from theground be repeated by the pilot to assure the accuracy of reception. Foruse of the present invention, the symbol AK can be employed to causeautomatic retransmission and automatic parity check against the originaltransmission. This, in turn, will permit the ground controller to turnhis attention to a second aircraft even before receipt of acknowledgmentfrom the first.

It is also to be noted that a number of the standard messages requiresubsequent transmission of digits. This may be accomplished through theuse of an automatic shift when decoding logic in the transmissioncircuitry recognizes the particular combinations. The messages whichrequire subsequent transmission of digits include:

Char- Ground to Air Air to Ground acter Transmission Transmission l7AltiMeter setting is not used XXXX 26 not used in this format FlightLevel is XXX 39 Go To (altitude XXX) Going To (altitude) XXX 41 Hold atAltitude XXX Holding Altitude XXX 44 Hold Heading XXX holding HeadingXXX 48 Hold Speed at XXX Holding Speed at XXX 58 Increase Speed to XXXIncreasing Speed to XXX 68 not used in this format Lowest Speed possibleis XXX 69 Locate Traffic at XXX not used in this format 79 OUter markeris XXX not used in this format 82 Slow Down to XXX knots Slowing Down toXXX knots 86 Report at Level (alt) Reporting at Level XXX XXX 92 TrafficDelay estimate not used in this format is XXX 96 Turn Left to TurningLeft to XXX XXX heading heading 98 Turn Right to Turning Right to XXXXXX heading heading Without going into detail herein, it is further tobe noted that the inclusion of specific alpha capabilities permitsmodification of standard messages and also emergency messages such asmight be required should the pilot be forced to undertake a collisionavoidance course change. Also, because the messages are so short, ratherthan employ a back space key, when an entry error is made the entiremessage may be eliminated by depressing a cancel key. Since all of thestandard messages as noted above start with alphas, but may end withnumerics, a dash or space key is provided to permit the generation ofmultiple message units. In the embodiment being described, the space keyserves as an automatic shift key to return the alphas for the start ofthe next message unit.

Referring now to FIGS. 2 and 3, circuitry in accordance with anembodiment of the invention intended for use in an air traffic controlenvironment is shown in block diagram form. The circuitry of FIGS. 2 and3 illustrates the principals of double keying and the logic required toimplement this keying technique. In FIG. 2 a keyboard 10, which may bearranged in the same manner as the keyboard of FIG. 1, is used to entera message in the logic circuitry. The entered message is presented on aprinter or a volatile display 12 in real time for proofreading and issimultaneously stored in binary form in a storage device 14 so that,when proofreading is completed, the message may be transmitted at highspeed to a remote terminal. The transmission may, of course, be by radiowaves and an exemplary remote terminal is depicted in FIG. 3. Thereceived message may be used to activate a speech synthesizer 16in theremote terminal which then pronounces the message at a normal speakingrate.

In the operation of the embodiment of FIGS. 2 and 3, the first key-pressis encoded into binary form in a twelve line to binary encoder 18. Theencoded signal commensurate with the first key-press is thereafterstored in a first four bit latch 20. The second key stroke is encoded byencoder l8 and stored in a second four bit latch 22. The eight bits ofdata thus generated and stored in latches 20 and 22 are presented to aread only memory 24 which adjusts the dual binary code to a codecompatible with the display device 12 and voice synthesizer 16. Thewords or characters are stored and displayed on a real time basis forproofreading before transmission, under the control of display storageand control circuit 26, and are simultaneously stored in a first-infirst-out (FIFO) register which comprises storage device 14. Each entryinto FIFO register 14 incre-' ments a counter 28 which counts the numberof entries. The counter 28 will be counted down to zero as data aretaken out of FIFO register 14 for transmission. When a complete messageis entered, a transmission button located remotely of the keyboard 10 ispressed thereby generating a signal which clears the display, if displaydevice 12 is a volatile display rather than a hard copy printer, andturns on a parallel-to-serial converter 30 and associated transmitter32. The transmit signal also initiates the operation of a furthercounter 34 which controls a pre-programmed identification message readonly memory 36. Counter 34 is incremented with each word transmitteduntil the complete identification message is transmitted. An AND/ORlogic selector array 38 then selects the output of FIFO register 14 anddelivers the keyboard-entered message from storage device l4 toconverter 30 for transmission. Each' word transmitted decrements theword counter 28 until it reaches zero, commensurate with completemessage transmitted, at whichtime the counter 28 causes the generationof a control signal which results in converter 30 and transmitter 32being turned off and the system readied for the next data entry.

The above briefly described entry, storage and transmission circuitrywill now be described in greater detail. Before using-the system, aclear button 38 is depressed to generate a signal which, under thecommand of steering logic 40, initializes the system. The clear switch38 will typically be located remotely of the keyboard and the signalgenerated thereby will result in the following functions beingaccomplished:

1. Clear the display storage and control circuit 26 thus also clearingdisplay 12; 2. Clear the FIFO register 14-thereby also clearing theparallel-to-serial converter 30;

I 3. Reset the up/down message word counter 28 to zero thereby alsosetting the output of a zero detector 42 to zero;

4. Reset the message present register 44 to the message not present"state;

5. Reset a transmit register 46 to the not transmit state;

6. Reset a number next" register 48 to the no number next state; and

7. Reset the steering logic 40 to accept the first key stroke of atwo-key stroke input character.

8. Reset the preprogrammed message word counter 34 to zero.

To enter a two-key stroke character, which will typically correspond toa spoken word from the voice synthesizer 16 of FIG. 3, any one of the 12keyboard keys other than the space key is depressed. The 12 lines ofdata from keyboard 10 are encoded by the 12 line-tobinary encoder 18 andpresented at the inputs of the two four-bit latches 20 and 22. The l2line to binary encoder 18 may, for example, comprise a plurality of RCAtype CD4002A and CD401 lA logic gates interconnected to assign a uniquebinary code to each input line while the four-bit latches 20 and 22 maycomprise RCA type CD4042A quad latches.

When the first key is depressed a key press detector circuit 50 providesan input signal to steering logic 40 via a delay circuit 52. The purposeof the delay imparted by circuit 52 is to allow the encoded informationto settle at the inputs of the latches 20 and 22 prior to theappropriate latch or latches being clocked by an output signal providedby steering logic 40. The clock signal provided by steering logic 40will cause the fourbit signal commensurate with the first key depressedto be temporarily stored in latch 20. The key press detector 50 may alsobe an RCA type CD4002A and CD40! IA logic gate array arranged as an OR"function of the 12 key lines and the delay circuit 52 may comprise anRCA type CD401 3 flip-flop circuit or equivalent. The steering logic 40,which provides alternate clocking signals for latches 20 and 22, maycomprise an RCA type CD4013A flip-flop, RCA type CD40llA and typeCD4001A gates and RCA type CD4009A inverters interconnected to give thefollowing performance. The clear signal from switch 38 will set theflip-flop, which is connected in a toggle mode, whereby the flip-flop isready to receive the first key stroke. A subsequent signal from delaycircuit 52 toggles the flip-flop and thus sends a positive voltage levelchange to latch 20. Another signal from delay 52 toggles the flip-flopthereby sending the positive signal to latch 22. The next signal fromdelay 52 will cause, in the same manner, the signaling of latch 20again. This action continues as two-keystroke characters are entered. Ifthe space key is depressed, both latches are signaled when delay 52causes the flip-flop to be toggled thereby entering a space. The spacekey generated signal also sets the flip-flop to be ready for asubsequent first key stroke. Similarly, a logic high, indicative ofnumber next, from register 48 will enable both latches to be signaledwhen delay 52 signals the flipflop. v

The system remains in the above described state until a second keydepression is sensed. The second key stroke is encoded in the samemanner as the first and is presented to the inputs of latches 20 and 22.The second key stroke is also detected 'by the key press detector 50which, after the delay imparted by delay circuit 52 in the interest ofallowing the data to settle at the inputs of the latches, signals thesteering logic 40 which clocks latch 22- and stores the second keystroke therein. At this stage, the two latches 20 and 22 hold eight bitsof data which are uniquely defined'by the two key strokes and theseeight bits are individually presented to the input of the read-onlymemory input converter 24. The read-only memory code converter 24, whichmay comprise a plurality of Intel type 1702 programmable read-onlymemories, transforms the unique input data into a unique coded wordaddress which is recognized and used by the voice synthesizer and thereal time display 12.

The signal which strobes or clocks latch 22 after the second key strokealso, after a delay imparted by circuit 54, clocks the FIFO storageregister 14, the display storage and control circuit 26 and the up/downmessage word counter 28. The delay circuit 54, which may comprise an RCAtype CD4013A flip-flop, imparts a time delay which allows the outputdata from code converter 24 to settle at the inputs to the FIFO storageregister 14 before being clocked into the storage register. The FIFOstorage register 14 may, for example, comprise a plurality of Fairchildtype 3341 storage registers while the up/down message counter 28 maycomprise a series of cascaded RCA type CD4029A counters. The displaystorage and control circuit 26 will be commensurate with display 12 andthe two units will typically be acquired as a single commerciallyavailable display unit.

After being clocked by the delayed latch 22 strobing pulse, FIFO storageregister 14 will have the first eightbit word stored in its firststorage location. The display storage and control circuit 26 also storesthe first eightbit word and displays the symbol or word on the display12. The up/down message word counter 28 increments each time a word isentered into the FIFO storage register 14. A zero detector 42 connectedto counter 28 changes state when the up/down counter 28 is clocked. Zerodetector 42 may, for example, comprise a series of RCA type CD4002A andCD401 lA gates connected to perform a NOR function whereby detector 42will provide a high output when the binary output of counter 28 is zeroand a low output at all other times.

Subsequent to completion of the operations described above, the steeringlogic 40 is now ready for the first key press of another two-keypressentry. If the next key press is a space key, the steering logic issignaled directly via conductor 39 and both of latches 20 and 22 arestrobed thereby storing the binary representation of the space key inboth latches. The logic then proceeds as if two keys had beensequentially depressed and stores a space code in the FIFO storageregister 14 and the display storage and control circuit 26; displaydevice 12 thus displaying a space.

After depression of the space is again ready for the first key strokeof. a two key stroke pair. If the two key strokes of a pair define aword which in the specialized usage indicated above is always followedby a number, this fact will be detected by read-only memory 24 as aconsequence of its programming. Read-only memory 24 will, accordingly,recognize the combinations which are to always be followed by numbersand will generate a signal commem surate with this information forapplication as'the' data key, the steeringlo gi'c input to a number nextregister 48. The number next" register 48 has applied, as control inputsthereto, a signal generated by depression of the space key and thedoubly delayed output commensurate with the strobing of latch 22; thesecond delay being imparted by delay circuit 58 which may comprise anRCA type CD4013A flip-flop. The number next register 48 may comprisemerely an RCA type CD4013A flip-flop circuit which is sampled by thedoubly delayed strobe pulse from the delay circuit 58. When sampled,register 48 transfers the data input from converter 24 to its outputterminal thereby signaling the steering logic that the next key pressesare to be treated as space key presses and stored in both latches. Theinformation transferred from the input to the output of next numberregister 48 is also fed back to the input of code converter 24 andsignals the code converter that the eight lines of input informationgenerated by the strobing of both of latches 20 and 22 is not a normaldouble key press but rather a number whose value is determined by theredundant information contained in both of latches 20 and 22. The delayimparted by circuit 58 will be sufficiently long to insure that theinput address of code converter 24 does not change until the eight-bitword from the code converter read-only memory has been stored in bothFIFO storage register 14 and display storage and control circuit 26.

Each key stroke after an entry which is determined as having numbersfollow it by the code converterread only memory 24 is stored in theabove described manner after a single key press until such time as thespace key is pressed. The depression of the space key, in the mannerdescribed above, enters a space into FIFO storage register 14 anddisplay storage and control 26 and resets the number next register 48.This action, in turn, returns the steering logic 40 to its normalroutine of entering two key strokes.

The above described process of entering information continues, eachcharacter incrementing the up/down message word counter 28 as a word isentered into the storage register 14, until the complete message hasbeen entered. After the complete message has been entered, the operatorproofreads the message on display 12 and transmit it by depressing thetransmit button 60. The momentary closing of the transmit switch 60 setsthe message present" register 44 to the message present state and sets amessage control register 62 to the preprogrammed message state. Thesetting of message control register 62 signals the AND/OR select network38 to gate a preprogrammed message to the transmitter in the manner tobe described below. The message present register 44 and message controlregister 62 may each comprise an RCA type CD4013A flipflop circuit. TheAND/OR selector network 38 may comprise a pair of RCA CD4019A gates anda CD4009A inverter connected so as to transfer either the eight lines ofdata from register 14 or the eight lines of data from ROM 36 to theparallel-to-serial converter 30 depending on the logic state of the dataselect line from message control register 62.

The state of message control register 62, in addition to being appliedas a control input to AND/OR selector network 38, is delivered as aninput to a clock distributor 64. The clock distributor 64, which maycomprise an array of RCA type CD401 1A gates, type CD4009A inverters andan RC differentiator circuit. Distributor 64, upon receipt of a signalfrom register 62 commensurate with transmit signal being received,provides a clock out signal to register 14'. This clock out" signalcauses the first character entered from the keyboard to be transferredto the output of register 14. The output of distributor 64, byapplication to counter 34, also enables further signals from converter30 to pass through a counter 34. However, after a further signal fromregister 62, indicative of preprogrammed message transmission completed,the signals from converter 30 are passed to register 14 to clock out theregister and to count message counter 28, rather than counter 34, downuntil the complete message is transmitted. To describe the operation inmore detail, clock distributor 64 generates signals for clocking thepreprogrammed identification word counter 34 and for resetting messagecounter 28 to zero. However, clock distributor 64 does not provideoutput signals until being enabled by an output from theparallel-to-serial output converter 30. The transmit signal generated bythe closing of switch 60 is delayed, by means of a delay circuit 66, toinsure that the message present register 44 and the message controlregister 62 are set correctly and the transmit signal is thereafteremployed to activate the transmit register 46. The activation or settingof transmit register 46 enables the parallel-to-serial converter 30which, in turn, gates clock distributor 64 thereby permitting the clockdistributor to send one clock pulse to the preprogrammed identificationmessage word counter 34. The clock pulse applied to counter 34 fromdistributor 64 allows the preprogrammed identification word counter tocount to binary one and the output of counter 34 is presented at theaddress input of the preprogrammed identification message read onlymemory 36.

Read only memory 36 is programmed with a unique identification message,for example an aircraft flight number and other identifying information,in the form of a series of words stored in such a manner that the wordsto be transmitted sequentially are stored with addresses in a binarycount mode. Thus, the first identification word has binary addressnumber one, the second word has binary address number two, etc. throughaddress word N which is the last word in a preprogrammed identificationmessage which has binary address N. To briefly describe the transmissionof the identification message, the read only memory 36 will presentidentification message word number one through the AND/OR select gatearray 38 to the transmitter 32 via the parallel-to-serial converter 30and a MODEM (modulator/demodulator) which will be associated withtransmitter 32. When the transmitter is ready to transmit the next word,the parallel-to-serial converter 30 signals clock distributor 64 whichsends a second clock pulse to message counter 34. The message counterthereupon addresses identification message word number two in read onlymemory 36 and causes this word to be presented to the transmitter in theabove described manner. This mode of operation will continue untilidentification message word number N l is addressed in read only memory36 by counter 34. The address commensurate with identification messageword N 1 is recognized by an end of preprogrammed message detector 68which signals message control register 62 that the identificationmessage has been transmitted. The message control register 62 isthereupon reset and, in turn, gates clock distributor 64. This actioncauses the clocking pulses generated by distributor 64 to be switchedfrom the input to counter 34 to the clock down and clock out inputsrespectively of up/down counter 28 and FIFO storage register 14. Theswitching control signal from message control register 62 is, inaddition to application to clock distributor 64, applied to the dataselect input of AND/OR selector network 38 and causes network 38 toswitch the output of storage register 14 to the transmitter. The firsteightbit keyboard character is now presented to the MODEM in thetransmitter 32 via the parallel-to-serial converter 30. The converter30, when the transmitter has completed the transmission of the firsteight-bit word, will signal clock distributor 64 which sends a furtherclock pulse to upldown counter 28 and register 14. The up/down counteris decremented one binary count and the second keyboard enteredeight-bit word is presented to the transmitter. This sequential indexingand transmission of the keyboard entered message continues until thelast word of the message has been transmitted as indicated by up/downcounter 28 reaching zero. The zero state of counter 28 is detected byzero detector 42 which again changes state thereby resetting the messagepresent register 44 to the message not present state. The resetting ofregister 44, in turn, causes the transmit register 46 to be reset to thenot transmit state thereby turning off transmitter 32.

y In one embodiment of the invention the identification word counter 34comprises an RCA type CD4024A binary counter and the programmedidentification message read only memory 36 is an Intel type 1702programmable ROM. The end of preprogrammed message detector 68 comprisesan array of RCA type CD4002A gates, type CD401 lA gates and type CD4009Ainverters interconnected to give a high output to the message controlregister 62 when counter 34 contains the address of preprogrammedidentification message word N l, and a low output at all other times.The parallel to serial converter 30 and transmitter 32 comprises aMotorola Model No. MC2257L transmitter used in association with anycommercially available MODEM. The delay circuit 66 is identical to delaycircuit 54 and the transmit register 46 comprises merely an RCA typeCD4013A flip-flop circuit.

Upon completion of the message entry and transmission cycle, asdescribed above, the system must be made ready for another cycle. Thismay be accomplished by depressing a clear all key 70 or, alternatively,the transmitter-off signal from transmit register 46 may be utilized toclear the system; for example in the same manner as shown with respectto the display storage and control circuit 26.

Referring now to FIG. 3, the message receiver system comprises areceiver 80 which includes a serial-toparallel converter. Receiver 80may, for example, comprise a Motorola Model No. MC2254L terminalreceiver. The received message is translated from serialto-parallelformat and eight lines of data are presented by receiver 80 to the inputof a first in first out (FIFO) register 82. As each word is entered intoFIFO register 82, an up/down counter 84 is clocked up one binary count.Subsequent to the clocking of counter 84, the voice synthesizer 16 istriggered and, as it finishes a word, the finished pulse will beemployed to count down counter 84. The finished pulse from synthesizer16 also, through a delay, causes retriggen'ng of the synthesizer. Thisaction continues until the up/down counter 84 returns to the zero statecommensurate with the message being completely read-out of FIFO storageregister 82 at which time the synthesizer trigger pulses are terminated.

To describe the receiver system in more detail, the operation of thereceiver starts with a transmitted message activating receiver whichtakes the incoming eight-bit serial words and converts them, toeight-bit parallel words. Receiver 80 also generates a character readypulse when a complete character has been received. The eight-bitparallel words from receiver 80 are presented to the input of FIFOregister 82 which may comprise a plurality of Fairchild Model 3341storage registers. The character ready pulses are applied to the clockin" input to register 82 and cause the storage register to store theeight-bit words in sequential storage locations. The character ready"pulse is also employed to clock up the up/down word counter 84, whichmay comprise an RCA type CD4029A binary counter, each time a characteris ready and entered into register 82. The first character ready pulsecommensuratewith'a transmitted message is also employed to turn on amessage present register 86. The message present register may comprisemerely an RCA type CD40l3A flip-flop circuit. A signal commensurate withthe setting of message present register 86 is capacitively coupled, viaa delay circuit 88 which imparts sufficient delay to allow the first fewwords transmitted to settle in storage register 82, to the clock outinput of register 82 via OR gate 96. The clocking of register 82presents the first character entered into the first in-first out storageregister at the input of the voice synthesizer l6. Delay circuit 88 maycomprise merely an RCA type CD4013A flip-flop circuit. The

delayed signal commensurate with the setting of mes- I sage presentregister 86 is also applied to an enable gating circuit 90. Gatingcircuit 90 may comprise an array of RCA type CD4OI1A gates, a typeCD4009A inverter and an RC differentiator circuit. When the data linefrom delay 88 goes high," gating circuit 90 sends a pulse to synthesizerl6 and counter 84, During the time the input to gating circuit 90 ishigh,'sign als coming from delay 94 are passed through circuit 90 tosynthesizer 16 and counter 84. When the input from delay 88 is returnedto a low state, gating circuit 90 blocks the signal from delay 94. Thus,the start command from gating circuit 90 allows synthesizer 16 to speakone word determined by the eight-bits of input information. The startcommand also clocks down one binary count from up/down counter 84 eachtime it ac-' I generates a ready next word signal which is applied toFIFO storage register 82 via OR gate 96, and also to a delay circuit 94.The ready next wor signal thus causes storage register 82 to present thenext word that has been entered therein in sequence to the voicesynthesizer input. The delay circuit 94, which may be identical to delaycircuit 88, provides time for the data from storage register 82 tosettle at the voice synthesizer input before permitting the synthesizerto retrigger itself via gating circuit 90. This action will continuewith data loaded into the FIFO storage register 82 from receiver 80being taken out of the storage register by the voice synthesizer untilthe up/down counter 84 reaches zero. The counter 84 will reach zero whenthe complete message has been generated by the voice synthesizer becausethe synthesizer has a much slower data rate than the transmitter andreceiver. A zero detector 92, which may comprise an array of RCA typeCD4002A and CD401 lA logic gates interconnected to perform a NORfunction. Zero detector 92 senses the condition of zero count in up/downword counter 84 and generates a control signal for the message presentregister 86. That is, detector 92 provides a logic high output tomessage present register 86 when the output of counter 84 is a binaryzero and provides a logic low at all other times. The message presentregister 86 thereupon, via the delay 88, interrupts the next word ready"signal from the voice synthesizer by resetting gating circuit 90 andthus stops the selftriggering of the voice synthesizer. Accordingly, thesound generation is terminated and the system remains ready to receivethe next transmitted message. Voice synthesizer 16 may, of course, bereplaced by or parallelled with a visual and/or hard copy displaydevice.

The embodiment of the invention described above is a rather complexsystem specifically intended for use in an air traffic controlenvironment. It will be obvious to those skilled in the art that variousmodifications and substitutions may be made, without the exercise ofinvention, in the interest of utilizing the invention in less demandingenvironments. Accordingly, it is to be understood that the presentinvention has been described by way of illustration and not limitation.

It should also be obvious that by the use of a minor change in the ICAOphonetic alphabet involving the substitution of such words as George,Isaac, Larry and Zebra, respectively, for Golf," India, Lima and Zulu,sequential keying of the first two letters of the words of this revisedvocabulary on the existing Bell Touchtone Keyboard yields combinationswhich uniquely define the desired letters. This permits the use oftelephone lines for the transmission of hard copy or for computerinterrogation with no requirement for special equipment at theoriginating end of the system.

What is claimed is:

1. Keyboard entry communications apparatus comprising:

keyboard means, said keyboard means having character entry keys fewer innumber than the total number of characters comprising the language inwhich information is to be communicated;

means connected to said keyboard means for encoding signals produced bythe operation of each key on said keyboard means;

a plurality of storage devices connected to said encoding means fortemporarily storing encoded signals commensurate with key operations;

steering logic means connected to said keyboard means and responsive toeach key operation for generating and applying enabling signalssequentially to said temporary storage devices whereby successive keyoperations will result in an encoded signal being accepted by adifferent one of said temporary storage devices;

memory means connected to said temporary storage devices and responsiveto the enabling of the last storage device in sequence for accepting andstoring encoded information from all of said temporary storage devices,said information from all of said temporary storage devices beingcommensurate with a unique character defined by a plurality ofsuccessive key operations;

transmitter means connected to said memory means for transmittingmessages stored in said memory means, said messages comprising aplurality of characters each uniquely defined by a plurality of keyoperations; and

means for selectively enabling said transmitter means.

2. The apparatus of claim 1 wherein said keyboard means includes a spacekey and wherein said steering logic means is responsive to operation ofthe space key for generating a signal for simultaneously enabling all ofsaid temporary storage devices whereby an encoded signal commensuratewith a space will be applied to said memory means upon operation of thespace key.

3. The apparatus of claim 2 further comprising:

display means for providing an intelligible presentation of informationentered by said keyboard means on a real time basis, said display meansbeing connected to said memory means and responsive to the entry ofencoded information therein for providing an indication of suchinformation.

4. The apparatus of claim 3 wherein said encoding means comprises:

a binary encoder; and wherein said communications apparatus furthercomprises:

means connected between said temporary storage means and said memorymeans for converting the plural binary coded signals in said temporarystorage devices into a code compatible with said display means.

5. The apparatus of claim 1 further comprising:

means for storing a programmed identification message;

selector means having input terminals connected to said programmedidentification message storing means and said memory means, saidselector means having an output terminal connected to said transmittermeans; and

means responsive to command signals provided b said transmitter meansenabling means for controlling said selector means whereby saidprogrammed identification message and keyboard entered message aresequentially delivered to said transmitter means.

6. The apparatus of claim 3 further comprising:

means for storing a programmed identification message;

selector means having input terminals connected to said programmedidentification message storing means and said memory means, saidselector means having an output terminal connected to said transmittermeans; and

means responsive to command signals provided by said transmitter meansenabling means for controlling said selector means whereby saidprogrammed identification message and keyboard entered message aresequentially delivered to said transmitter means. 7. The apparatus ofclaim 4 further comprising:

means for storing a programmed identification message;

selector means having input terminals connected to said programmedidentification message storing means and said memory means, saidselector means having an output terminal connected to said transmittermeans; and

means responsive to command signals provided by said transmitter meansenabling means for controlling said selector means whereby saidprogrammed identification message and keyboard entered message aresequentially delivered to said transmitter means.

8. The apparatus of claim 1 wherein said keyboard means comprises:

a one-hand operated key set including ten alphanumeric informationassociated keys; and

means for providing a separate electrical output connection commensuratewith each key.

9. The key set of claim 8 wherein characters are associated with thekeys in alphabetical and numerical order.

10. The apparatus of claim 2 wherein characters defined by certain ofsaid plural sequential key operations will be commensurate with words tobe followed by numerical information and wherein said memory meanscomprises:

a read only memory, said read only memory identifying those words whichare to be followed by numerical information and generating a controlsignal commensurate therewith;

means responsive to control signals provided by said read onlymemory'for providing a signal to said steering logic means which resultsin all of said temporary storage devices being simultaneously enabled inresponse to each succeeding key operation until the space key isoperated.

11. The apparatus of claim 10 wherein said keyboard means comprises:

a one-hand operated key set; and

means for providing a separate electrical output connection commensuratewith each key on said key set. v

12. The apparatus of claim 11 wherein said encoding means comprises abinary encoder.

13. The apparatus of claim 12 wherein said memory means furthercomprises:

means connected between said temporary storage devices and said readonly memory for converting plural binary coded signals in said storagedevices into a code compatible to presentation to a human operator. I

14. The apparatus of claim 13 further comprising:

display means for providing an intelligible presentation of informationentered by said keyboard means on a real time basis, said display meansbeing connected to said read only memory means and responsive to theentry of encoded information sage are sequentially delivered to saidtransmitter means. 16. The apparatus of claim 1 wherein said encodingmeans comprises:

a binary encoder. 17. The apparatus of claim 16 wherein said memorymeans comprises:

means connected to the output terminals of said temporary storagedevices for converting plural binary coded signals from said storagedevices into a code compatible to presentation to a human subject; and

means connected between said code converter and said transmitter meansfor storing a complete message in the form of a plurality of charactersdefined by plural key operations.

18. The apparatus of claim 17 further comprising:

voice synthesizer means adapted to receive messages delivered out ofsaid storing means ,via said transmitter means in response to operationof said transmitter means enabling means. l9.'The apparatus of claim 18wherein said keyboar means comprises:

a one-hand operated key set including ten alphanumeric informationassociated keys; and

means for providing a separate electrical output connection commensuratewith each key.

20. The apparatus of claim 19 wherein said keyboard means includes aspace key and wherein said steering logic means is responsive tooperation of the space key for generating a signal for simultaneouslyenabling all of said temporary storage devices whereby an encoded signalcommensurate with a space will be applied to said code converting meansupon operation of the space key.

21. The apparatus of claim 20 further comprising:

display means for providingan intelligible presentation of informationentered by said keyboard means on a real time basis, said display meansbeing connected to said code converting means and responsive to theentry of encoded information therein for providing an indication of suchinformation.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONv Patent No.3,833,765 Dated September 3-. 7

Inventor(s) Edwin H. Hilborn, Joseph D. Vrabel and Kenneth J. Bray It iscertified that error appears in the above-identified patent and thatsaid Letters Patentare hereby corrected as shown below:

Under "Inventors, data element [75] on the front page,

the second inventor's name appears as "Joseph D. Brabel." v

and should be corrected to "Joseph D. vrabel Signed and sealed this 19thday of November 1974.

(SEAL)- Attest:

ucoY M. GIBSON JR. c. MARS ALL DANN Attesting Officer Commissloner ofPatents po'wso ($69) i USCOMM-DC scan-ps9 L5. GOVERNIENT PRINTING OFFICEI'll O-Si-Sl.

1. Keyboard entry communications apparatus comprising: keyboard means, said keyboard means having character entry keys fewer in number than the total number of characters comprising the language in which information is to be communicated; means connected to said keyboard means for encoding signals produced by the operation of each key on said keyboard means; a plurality of storage devices connected to said encoding means for temporarily storing encoded signals commensurate with key operations; steering logic means connected to said keyboard means and responsive to each key operation for generating and applying enabling signals sequentially to said temporary storage devices whereby successive key operations will result in an encoded signal being accepted by a different one of said temporary storage devices; memory means connected to said temporary storage devices and responsive to the enabling of the last storage device in sequence for accepting and storing encoded information from all of said temporary storage devices, said information from all of said temporary storage devices being commensurate with a unique character defined by a plurality of successive key operations; transmitter means connected to said memory means for transmitting messages stored in said memory means, said messages comprising a plurality of characters each uniquely defined by a plurality of key operations; and means for selectively enabling said transmitter means.
 2. The apparatus of claim 1 wherein said keyboard means includes a space key and wherein said steering logic means is responsive to operation of the space key for generating a signal for simultaneously enabling all of said temporary storage devices whereby an encoded signal commensurate with a space will be applied to said memory means upon operation of the space key.
 3. The apparatus of claim 2 further comprising: display means for providing an intelligible presentation of information entered by said keyboard means on a real time basis, said display means being connected to said memory means and responsive to the entry of encoded information therein for providing an indication of such information.
 4. The apparatus of claim 3 wherein said encoding means comprises: a binary encoder; and wherein said communications apparatus further comprises: means connected between said temporary storage means and said memory means for converting the plural binary coded signals in said temporary storage devices into a code compatible with said display means.
 5. The apparatus of claim 1 further comprising: means for storing a programmed identification message; selector means having input terminals connected to said programmed identification message storing means and said memory means, said selector means having an output terminal connected to said transmitter means; and means responsive to coMmand signals provided by said transmitter means enabling means for controlling said selector means whereby said programmed identification message and keyboard entered message are sequentially delivered to said transmitter means.
 6. The apparatus of claim 3 further comprising: means for storing a programmed identification message; selector means having input terminals connected to said programmed identification message storing means and said memory means, said selector means having an output terminal connected to said transmitter means; and means responsive to command signals provided by said transmitter means enabling means for controlling said selector means whereby said programmed identification message and keyboard entered message are sequentially delivered to said transmitter means.
 7. The apparatus of claim 4 further comprising: means for storing a programmed identification message; selector means having input terminals connected to said programmed identification message storing means and said memory means, said selector means having an output terminal connected to said transmitter means; and means responsive to command signals provided by said transmitter means enabling means for controlling said selector means whereby said programmed identification message and keyboard entered message are sequentially delivered to said transmitter means.
 8. The apparatus of claim 1 wherein said keyboard means comprises: a one-hand operated key set including ten alpha-numeric information associated keys; and means for providing a separate electrical output connection commensurate with each key.
 9. The key set of claim 8 wherein characters are associated with the keys in alphabetical and numerical order.
 10. The apparatus of claim 2 wherein characters defined by certain of said plural sequential key operations will be commensurate with words to be followed by numerical information and wherein said memory means comprises: a read only memory, said read only memory identifying those words which are to be followed by numerical information and generating a control signal commensurate therewith; means responsive to control signals provided by said read only memory for providing a signal to said steering logic means which results in all of said temporary storage devices being simultaneously enabled in response to each succeeding key operation until the space key is operated.
 11. The apparatus of claim 10 wherein said keyboard means comprises: a one-hand operated key set; and means for providing a separate electrical output connection commensurate with each key on said key set.
 12. The apparatus of claim 11 wherein said encoding means comprises a binary encoder.
 13. The apparatus of claim 12 wherein said memory means further comprises: means connected between said temporary storage devices and said read only memory for converting plural binary coded signals in said storage devices into a code compatible to presentation to a human operator.
 14. The apparatus of claim 13 further comprising: display means for providing an intelligible presentation of information entered by said keyboard means on a real time basis, said display means being connected to said read only memory means and responsive to the entry of encoded information therein for providing an indication of such information.
 15. The apparatus of claim 14 further comprising: means for storing a programmed identification message; selector means having input terminals connected to said programmed identification message storing means and said memory means, said selector means having an output terminal connected to said transmitter means; and means responsive to command signals provided by said transmitter means enabling means for controlling said selector means whereby said programmed identification message and keyboard entered message are sequentially delivered to said transmitter means.
 16. The apparatus of claim 1 wherein said encoding means comprises: a binary encoder.
 17. The apparatus of claim 16 wherein said memory means comprises: means connected to the output terminals of said temporary storage devices for converting plural binary coded signals from said storage devices into a code compatible to presentation to a human subject; and means connected between said code converter and said transmitter means for storing a complete message in the form of a plurality of characters defined by plural key operations.
 18. The apparatus of claim 17 further comprising: voice synthesizer means adapted to receive messages delivered out of said storing means via said transmitter means in response to operation of said transmitter means enabling means.
 19. The apparatus of claim 18 wherein said keyboard means comprises: a one-hand operated key set including ten alpha-numeric information associated keys; and means for providing a separate electrical output connection commensurate with each key.
 20. The apparatus of claim 19 wherein said keyboard means includes a space key and wherein said steering logic means is responsive to operation of the space key for generating a signal for simultaneously enabling all of said temporary storage devices whereby an encoded signal commensurate with a space will be applied to said code converting means upon operation of the space key.
 21. The apparatus of claim 20 further comprising: display means for providing an intelligible presentation of information entered by said keyboard means on a real time basis, said display means being connected to said code converting means and responsive to the entry of encoded information therein for providing an indication of such information. 